/ln-12-product-requirements-builder

name: ln-12-product-requirements-builder
description: "Defines product requirements, business rules and acceptance criteria for a committed intent; edits product docs only."

Product Requirements Builder

**Goal:** Create or update a usable product requirements artifact that preserves the owner's intent and makes expected behavior testable. Change only authorized product documentation; do not invent commitments, design architecture, or implement.

**Execution contract:** Track every checklist item as `PENDING`, `PROVEN` with observed outcome evidence, `CLEARED` with evidence its condition is absent, or `UNPROVEN` with a gap. Reading, delegation, tool failure, zero exit status, and self-reported success are not proof. Reconcile after each section; before returning, resolve all `PENDING`, count only `PROVEN` and `CLEARED`, and apply verdict and approval rules to every gap. Preserve intent, scope, mode, and existing authorization. Complete authorized work before required external approval; ask only consequential unresolved choices. If nobody can answer, report the exact question and apply the skill's gap verdict without waiting or guessing. Cite any blocking instruction and unresolved boundary; never invent approval gates. Scale depth to material risk; preserve mandatory checks, dependencies, and safety order while choosing verification methods. Accept equivalent user or repository evidence without requiring another skill, named artifact, or full lifecycle. Preserve source requirement and decision IDs. Bind reused evidence to relevant versions, dirty changes, configuration, environment, and observation windows; invalidate only affected claims. Choose the primary workflow by outcome and explicit selection. Consume neighboring contracts and valid evidence without duplicating ownership or restarting audits. Split distinct deliverables by scope, not mandatory skill invocation. Broad independent assessments use audit workflows; focused domain reviews remain read-only. On continuation, reconcile task, authorization, state, and gaps. Return a compact continuation record for long work or update an already authorized artifact; read-only skills do not persist it. Distinguish artifact readiness, verified behavior, and external-action authority. Trace applicable requirements to their authoritative owner, planned or implemented change, acceptance evidence and status in the existing artifact or response; no new registry is required. Explicit constraints remain binding until an authorized deviation; risk determines priority, not permission to ignore them. Investigate the causal flow beyond initially named files. Within implementation authority, include structural repair needed for the outcome; minimize total complexity and risk, not changed lines. This does not authorize unrelated cleanup or mutation during review. Before retrieval, define the evidence question; read selectively without skipping applicable instructions. Use tools for mechanical processing; summarize bounded results, errors, coverage, and source paths, keeping full output outside context. Before technical decisions, establish applicability and actual versions; verify version-dependent assumptions against official documentation or specifications. Search and read primary pages for current external recommendations; snippets are not evidence. Version-matched bundled documentation or valid prior evidence suffices. Record decision, version, source, and limitations. Mark unavailable evidence UNVERIFIED; block only essential dependent work. Prefer native mechanisms, justify added tools or abstractions with evidence, and reuse the existing rule owner.

Tool Routing

| Need | Preferred capability | Fallback | |---|---|---| | Intent and prior decisions | User request, product documents and accepted decisions | Bounded assumptions; ask only for missing consequential intent | | Existing behavior | Focused repository, UI, contract and analytics evidence | Supplied examples with explicit uncertainty | | Requirement artifact | Existing canonical product document and focused editor | User-approved destination; BLOCKED if no safe destination is available |

Domain Rules

• Reuse the existing requirement owner; otherwise use an authorized docs/product/requirements.md. Do not impose a new document hierarchy on an established project.
• Separate observed behavior, owner preference, proposed requirements, accepted commitments, and unresolved choices. A discovery recommendation is not authorization to build.
• Use stable requirement identifiers when traceability spans artifacts. Keep functional rules here and reference architecture constraints by source; user stories are optional representations.

Checklist

1. Establish Intent and Authority

• [ ] Resolve the problem, affected actors, intended outcome, horizon, approved documentation scope, and protected existing experience.
• [ ] Read repository instructions, relevant user evidence and existing requirements; inspect target files and user changes before editing.
• [ ] Identify one authoritative requirements destination and applicable decision owners; preserve unresolved conflicting sources.
• [ ] Separate non-goals, optional ideas and committed scope; clarify only choices that change acceptance or product intent.

2. Specify Observable Behavior

• [ ] Describe the initiating event, actor permissions, preconditions, successful outcome and meaningful alternatives for every in-scope journey.
• [ ] Specify business rules, calculations, entities and lifecycle transitions where they determine observable behavior.
• [ ] Specify applicable failure, empty, loading, retry, duplicate, cancellation and recovery behavior without inventing irrelevant states.
• [ ] Record affected integrations, external commitments, compatibility and data constraints from authoritative sources.
• [ ] Capture accessibility, privacy and other applicable user-facing constraints; reference architecture-driving targets